The present invention relates to the field of on-board methods and systems to assist piloting of an aircraft and, more specifically, to alert the crew that a stall is imminent, and to assist them to control the aircraft.
Stalling consists of a sudden loss of lift of the aircraft which may be due to a very high angle of incidence (or angle of attack) between the chord line of a wing and the aircraft's speed vector. More specifically, when the pitch angle increases the angle of attack increases, lift increases, and the flow over the top surface of a wing starts to separate in the area of the trailing edge. When the angle of attack reaches a critical value (called the stall value), which depends on the wing's characteristics, an air flow separation may occur on the top surface of the wing, leading to a loss of lift.
Each wing generally has a sensor (for example, a tongue positioned on the edge of the wing) to measure the current value of the angle of attack. The measurement is transmitted to an indicator on the instrument panel giving the current value of the angle of attack.
In addition, when the angle of attack begins to come close to the stall value, the angle of attack measurement sensor activates cabin alerts of a visual, and/or acoustic and/or tactile (stick vibration) type. The pilot then pushes the stick to regain an angle of attack which is lower than the stall value.
The various alerts thus enable the crew to remedy the situation in order that the aircraft does not stall. However, these alerts do not provide assistance with piloting to facilitate re-establishment of control of the aircraft.
In addition, the crew does not have precise indications enabling them, if required, to increase lift fully without exceeding the stall angle of attack.
The object of the present invention is to propose a system and method to assist piloting which is simple, intuitive and accurate, remedying the abovementioned disadvantages, and in particular providing the crew with visual detection means which are easy to interpret, in order not to enter into a stall, and a real system to assist piloting in order to control the aircraft in stall situations.